Very long years ago, freight wagons can load only one type of freight.Recently, we achieved carrying multiple types of freight in a box --- which is called "container".In simutrans, there's no way to simulate this feature, I think.

So, I propose that introducing new .dat parameter for goods like "container_freight".If the good can be carried in container, the flag is set 1. If no, set 0.And more, we should create new special good named "Container". Container can carry all types of good that are set "container_freight=1".

This is an interesting idea, but I am not sure exactly how it would work, especially how it would interact with the system of pathfinding and the way in which routes are cached. Can you elaborate a little on how you would imagine that this would work in practice?

(I should note that I am not likely to be able myself to work on any substantial new feature not already in the list of features to be developed for many, many years owing to the very long list of priority balancing features and bug reports, but I know that a number of others are increasingly working on features for Simutrans-Extended at present, which is splendid).